arXiv subjects

Robert Franken

Publications and source records attributed to Robert Franken.

8 recordsLinked to original sources

arXiv2026

The cleanest of them all: NLO electroweak corrections to vector-boson scattering into doubly polarised ZZ pairs at the LHC

We present the first calculation of the next-to-leading-order electroweak corrections to vector-boson scattering into doubly polarised Z bosons at the LHC in the fully leptonic decay channel. The production and decay of the two polarised Z bosons are consistently modelled in the double-pole approximation, separating polarisation states at the amplitude level and including factorisable real and virtual electroweak corrections. Doubly polarised and unpolarised signals are investigated and confronted with off-shell results. A broad analysis, including results at integrated and differential level, is carried out in a realistic, CMS-inspired fiducial setup. Our study paves the way to upcoming analyses with LHC Run-3 and High-Luminosity data as well as to further phenomenological investigations.

hep-ph↗

arXiv2026

NLO QCD and EW corrections to semileptonic vector-boson scattering at the LHC

Vector-boson scattering with semileptonic final states has recently been measured at the LHC, and future experiments are expected to further increase the precision of its measurement, calling for adequate theoretical predictions. In this work, we present a calculation of the NLO QCD and electroweak corrections to the process $\text{p}\text{p} \to \ell^+ ν_\ell + 4\text{j}$ in two different fiducial regions relevant for vector-boson scattering. In a fully off-shell calculation, we provide results for the leading electroweak contribution of $\mathcal{O}\left(α^6\right)$ and the corresponding corrections of $\mathcal{O}\left(α^7\right)$ and $\mathcal{O}\left(α_\text{s} α^6\right)$ for fiducial cross sections and a selection of differential distributions.

hep-ph↗

arXiv2025

Electroweak corrections to doubly polarised WZ scattering at the LHC

We present a calculation of next-to-leading-order electroweak corrections to the vector-boson scattering (VBS) process resulting in leptonically decaying W and Z bosons in association with two jets at the LHC. The VBS process is computed for both polarised and unpolarised intermediate bosons, exploiting the pole approximation and the separation of helicity states in tree-level and one-loop amplitudes. A phenomenological analysis is carried out for a realistic fiducial setup at a 13.6 TeV LHC collision energy, highlighting different patterns for the various polarisation states both at integrated and at differential level. This study provides theoretical predictions that are necessary to perform a sound characterisation of the spin structure of VBS processes with full LHC data.

hep-ph↗

arXiv2022

NLO QCD and EW corrections to vector-boson scattering into $\rm W^+W^-$ at the LHC

We present the full next-to-leading-order electroweak and QCD corrections to vector-boson scattering into a pair of off-shell opposite-sign W bosons decaying into leptons of different flavour at the LHC. We include full leading-order predictions for the irreducible background. Explicitly, we investigate the process ${\rm pp \to e^+ ν_eμ^-\barν_μjj} + X$ at leading orders $O(α^6)$, $O(\rmα_sα^5)$, $O(\rmα_s^2α^4)$, supplemented by the loop-induced $O(\rmα_s^4α^4)$ contribution, and at next-to-leading orders $O(α^7)$ and $O(\rmα_sα^6)$ in two setups providing fiducial cross sections as well as differential distributions. We take full account of photon-induced next-to-leading-order contributions, which prove to be non negligible. With $-11.4\%$ and $-6.7\%$ in the two setups, the electroweak corrections are smaller than for other vector-boson-scattering processes. This can be traced back to the presence of the Higgs-boson resonance in the fiducial phase space, whose effects we analyse within an additional unphysical, but manifestly gauge-invariant setup. The QCD corrections amount to $-5.1\%$ and $-21.6\%$ in the two setups. The large size of the latter correction, compared to other vector-boson scattering processes, is explained by a very restrictive definition of its fiducial phase space.

hep-ph↗

arXiv2022

Vector Boson Scattering Processes: Status and Prospects

Insight into the electroweak (EW) and Higgs sectors can be achieved through measurements of vector boson scattering (VBS) processes. The scattering of EW bosons are rare processes that are precisely predicted in the Standard Model (SM) and are closely related to the Higgs mechanism. Modifications to VBS processes are also predicted in models of physics beyond the SM (BSM), for example through changes to the Higgs boson couplings to gauge bosons and the resonant production of new particles. In this review, experimental results and theoretical developments of VBS at the Large Hadron Collider, its high luminosity upgrade, and future colliders are presented.

hep-ph↗

arXiv2021

Full NLO predictions for vector-boson scattering into Z bosons and its irreducible background at the LHC

Vector-boson scattering into two Z bosons at the LHC is a key channel for the exploration of the electroweak sector of the Standard Model. It allows for the full reconstruction of the scattering process but at the price of a huge irreducible background. For the first time, we present full next-to-leading-order predictions for $pp \to e^+e^-μ^+μ^-jj+X$ including all electroweak and QCD contributions for vector-boson scattering signal and irreducible background. The results are presented in the form of cross sections and differential distributions. A particular emphasis is put on the newly computed $O(α_s^2 α^5)$ corrections.

hep-ph↗

arXiv2020

NLO QCD and EW corrections to vector-boson scattering into ZZ at the LHC

We present the first calculation of the full next-to-leading-order electroweak and QCD corrections for vector-boson scattering (VBS) into a pair of Z bosons at the LHC. We consider specifically the process ${\rm pp\to e^{+}e^{-}μ^{+}μ^{-}jj}+X$ at orders $\mathcal{O}(α^7)$ and $\mathcal{O}(α_sα^6)$ and take all off-shell and interference contributions into account. Owing to the presence of enhanced Sudakov logarithms, the electroweak corrections amount to $-16\%$ of the leading-order electroweak fiducial cross section and induce significant shape distortions of differential distributions. The QCD corrections on the other hand are larger ($+24\%$) than typical QCD corrections in VBS. This originates from considering the full computation including tri-boson contributions in a rather inclusive phase space. We also provide a leading-order analysis of all contributions to the cross section for ${\rm pp \to e^{+}e^{-}μ^{+}μ^{-}jj}+X$ in a realistic setup.

hep-ph↗

arXiv2020

On-shell constructibility of Born amplitudes in spontaneously broken gauge theories

We perform a comprehensive study of on-shell recursion relations for Born amplitudes in spontaneously broken gauge theories and identify the minimal shifts required to construct amplitudes with a given particle content and spin quantum numbers. We show that two-line or three-line shifts are sufficient to construct all amplitudes with five or more particles, apart from amplitudes involving longitudinal vector bosons or scalars, which may require at most five-line shifts. As an application, we revisit selection rules for multi-boson amplitudes using on-shell recursion and little-group transformations.

hep-th↗